Flexibility in basal metabolic rate and evaporative water loss among hoopoe larks exposed to different environmental temperatures

The 'energy demand' hypothesis for short-term adjustments in basal metabolic rate (BMR) posits that birds adjust the size of their internal organs relative to food intake, a correlate of energy demand, We tested this hypothesis on hoopoe larks (Alaemon alaudipes), inhabitants of the Arabian desert, by acclimating birds for 3 weeks at 15 degreesC and at 36 degreesC, then measuring their BMR and total evaporative water loss (TEWL), Thereafter, we determined the dry masses of their brain, heart, liver, kidney, stomach, intestine and muscles of the pectoral region. Although mean body mass did not differ initially between the two groups, after 3 weeks, birds in the 15 degreesC group had gained mass (44.1+/-6.5g), whereas larks in the 36 degreesC group had maintained a constant mass (36.6+/-3.6g; means +/- S.D., N=6). Birds in the 15 degreesC group had a mean BMR of 46.8+/-6.9kJday(-1), whereas birds in the 36 degreesC group had a BMR of 32.9+/-6.3kJday(-1), values that were significantly different when we controlled for differences in body mass. When measured at 35 degreesC, larks in the cold-exposure group had a TEWL of 3.55+/-0.60gH(2)Oday(-1), whereas TEWL for birds in the 36 degreesC group averaged 2.23+/-0.28gH(2)Oday(-1), a difference of 59,2%, Mass-independent TEWL differed significantly between groups, Larks in the 15 degreesC group had a significantly larger liver, kidney and intestine than larks in the 36 degreesC group. The total increase in organ mass contributed 14.3 % towards the total mass increment in the cold exposure group, Increased food intake among larks in the cold group apparently resulted in enlargement of some of the internal organs, and the increase in mass of these organs required a higher rate of oxygen uptake to support them. As oxygen demands increased, larks apparently lost more evaporative water, but the relationship between increases in BMR and TEWL remains unresolved

The evaluation of group breeding schemes in relation to the structure of the breeding system

International audienc

Co-operative group breeding schemes for prolific lowland sheep breeds

International audienc

Regeneration characteristics of a swamp forest in northwestern Tasmania

The botanical composition and regeneration characteristics are described for a Melaleuca ricifoliaLeptospermum lanigerum forest from northwestern Tasmania. The size classes of the two dominant species are highly correlated with tree age. Size class analysis shows that the dominants are regenerating continuously. The relationship of this forest type to rainforest and wet sclerophyll forest are discussed

Symbiosis in the microbial world: from ecology to genome evolution

© 2018. Published by The Company of Biologists Ltd. The concept of symbiosis – defined in 1879 by de Bary as ‘the living together of unlike organisms’ – has a rich and convoluted history in biology. In part, because it questioned the concept of the individual, symbiosis fell largely outside mainstream science and has traditionally received less attention than other research disciplines. This is gradually changing. In nature organisms do not live in isolation but rather interact with, and are impacted by, diverse beings throughout their life histories. Symbiosis is now recognized as a central driver of evolution across the entire tree of life, including, for example, bacterial endosymbionts that provide insects with vital nutrients and the mitochondria that power our own cells. Symbioses between microbes and their multicellular hosts also underpin the ecological success of some of the most productive ecosystems on the planet, including hydrothermal vents and coral reefs. In November 2017, scientists working in fields spanning the life sciences came together at a Company of Biologists’ workshop to discuss the origin, maintenance, and long-term implications of symbiosis from the complementary perspectives of cell biology, ecology, evolution and genomics, taking into account both model and non-model organisms. Here, we provide a brief synthesis of the fruitful discussions that transpired

Optimizing fire station locations for the Istanbul metropolitan municipality

Copyright @ 2013 INFORMSThe Istanbul Metropolitan Municipality (IMM) seeks to determine locations for additional fire stations to build in Istanbul; its objective is to make residences and historic sites reachable by emergency vehicles within five minutes of a fire station’s receipt of a service request. In this paper, we discuss our development of a mathematical model to aid IMM in determining these locations by using data retrieved from its fire incident records. We use a geographic information system to implement the model on Istanbul’s road network, and solve two location models—set-covering and maximal-covering—as what-if scenarios. We discuss 10 scenarios, including the situation that existed when we initiated the project and the scenario that IMM implemented. The scenario implemented increases the city’s fire station coverage from 58.6 percent to 85.9 percent, based on a five-minute response time, with an implementation plan that spans three years

Physiological adjustments to arid and mesic environments in larks (Alaudidae)

Because deserts are characterized by low food availability, high ambient temperature extremes, and absence of drinking water, one might expect that birds that live in these conditions exhibit a lower basal metabolic rate ( BMR), reduced total evaporative water loss (TEWL), and greater ability to cope with high air temperatures than their mesic counterparts. To minimize confounding effects of phylogeny, we compared the physiological performance of four species of larks at ambient temperatures (T-a's) ranging from 0degrees to 50degreesC: hoopoe larks (Alaemon alaudipes) and Dunn's larks ( Eremalauda dunni) live in hot and dry deserts, whereas skylarks (Alauda arvensis) and woodlarks (Lullula arborea) occur in temperate mesic areas. Mass-adjusted BMR and TEWL were indistinguishable between hoopoe lark and Dunn's lark and between skylark and woodlark. When grouping the data of the two desert larks in one set and the data of the two mesic larks in another, desert larks are shown to have 43% lower BMR levels and 27% lower TEWL values than the mesic species. Their body temperatures (T-b's) were 1.1degreesC lower, and the minimal dry heat transfer coefficients ( h) were 26% below values for the mesic larks. When T a exceeded T-b, the h of hoopoe larks and Dunn's larks was high and indistinguishable from h at 40 degreesC, in contrast to the prediction that h should be decreased to minimize heat gain through conductance, convection, or radiation from the environment when T-a exceeds T-b